Avoid SetPropertyInternal if the LookupIterator is NotFound

BUG=

Review URL: https://codereview.chromium.org/1756883002

Cr-Commit-Position: refs/heads/master@{#34437}

src/objects.cc

@@ -4131,7 +4131,7 @@ Maybe<bool> Object::SetPropertyInternal(LookupIterator* it,
                                         LanguageMode language_mode,
                                         StoreFromKeyed store_mode,
                                         bool* found) {
-  it->UpdateProtector();
+  DCHECK(it->IsFound());
   ShouldThrow should_throw =
       is_sloppy(language_mode) ? DONT_THROW : THROW_ON_ERROR;
 
@@ -4139,7 +4139,7 @@ Maybe<bool> Object::SetPropertyInternal(LookupIterator* it,
   // interceptor calls.
   AssertNoContextChange ncc(it->isolate());
 
-  for (; it->IsFound(); it->Next()) {
+  do {
     switch (it->state()) {
       case LookupIterator::NOT_FOUND:
         UNREACHABLE();
@@ -4202,7 +4202,8 @@ Maybe<bool> Object::SetPropertyInternal(LookupIterator* it,
         *found = false;
         return Nothing<bool>();
     }
-  }
+    it->Next();
+  } while (it->IsFound());
 
   *found = false;
   return Nothing<bool>();
@@ -4212,10 +4213,13 @@ Maybe<bool> Object::SetPropertyInternal(LookupIterator* it,
 Maybe<bool> Object::SetProperty(LookupIterator* it, Handle<Object> value,
                                 LanguageMode language_mode,
                                 StoreFromKeyed store_mode) {
-  bool found = true;
-  Maybe<bool> result =
-      SetPropertyInternal(it, value, language_mode, store_mode, &found);
-  if (found) return result;
+  it->UpdateProtector();
+  if (it->IsFound()) {
+    bool found = true;
+    Maybe<bool> result =
+        SetPropertyInternal(it, value, language_mode, store_mode, &found);
+    if (found) return result;
+  }
 
   // If the receiver is the JSGlobalObject, the store was contextual. In case
   // the property did not exist yet on the global object itself, we have to
@@ -4237,10 +4241,13 @@ Maybe<bool> Object::SetSuperProperty(LookupIterator* it, Handle<Object> value,
                                      StoreFromKeyed store_mode) {
   Isolate* isolate = it->isolate();
 
-  bool found = true;
-  Maybe<bool> result =
-      SetPropertyInternal(it, value, language_mode, store_mode, &found);
-  if (found) return result;
+  it->UpdateProtector();
+  if (it->IsFound()) {
+    bool found = true;
+    Maybe<bool> result =
+        SetPropertyInternal(it, value, language_mode, store_mode, &found);
+    if (found) return result;
+  }
 
   // The property either doesn't exist on the holder or exists there as a data
   // property.
@@ -4315,8 +4322,7 @@ Maybe<bool> Object::SetSuperProperty(LookupIterator* it, Handle<Object> value,
     }
   }
 
-  return JSObject::AddDataProperty(&own_lookup, value, NONE, should_throw,
-                                   store_mode);
+  return AddDataProperty(&own_lookup, value, NONE, should_throw, store_mode);
 }
 
 MaybeHandle<Object> Object::ReadAbsentProperty(LookupIterator* it) {